Gossip Girl (ITV2, 10pm); Cane (ITV3, 10pm); Sleeping With My Sister (C4, 9pm)

DESPITE the blogger narrator, Gossip Girl resembles most other US teen soaps with bitchy girls, impossibly chiselled boys and parents too busy to notice, let alone show disapproval of, their offspring's social life.

The presence of The OC's Josh Schwartz and Stephanie Savage lets you know what to expect, although the setting is not Orange County but the wealthy end of New York.

The reappearance of Serena van der Woodsen (Blake Lively), who disappearing mysteriously to boarding school a year ago, sets the cat among the pigeons in school.

New queen bee Blair Waldorf (Leighton Meester) is put out because she knows her boyfriend Nate (Chace Crawford) had a thing for Serena. What she doesn't know - not yet, anyway - is that he "sealed the deal" with Serena, which is another way of saying he had sex with her.

This is a place where world conflicts take second place to "fashion emergencies" and where Blair probably thinks global warming is a new tanning method.

Nat does occasionally think (you can tell because he looks like he's in pain) as well as look tasty. "Do you feel our lives are planned out for us and we'll end up like our parents?"

he wonders in a rare moment of reflection.

None of these rich, spoilt brats are likeable.

The only teens vying for our sympathy are Jenny and Dan, and that's because they're not as well off as the others.

Underage drinking, attempted rape and the advantages of a little black dress over a red one are other dilemmas facing teens in the overcrowded scenario.

Cane is another US import, this one trying to do with sugar what Dallas did with oil.

Cane has two families at war. The Samuels want to buy the Dugue's sugar cane fields.

That would enable the Dugues to concentrate on making rum.

One of the Dugues is sleeping with the enemy (Polly Walker, the obligatory British member of the cast) just to add to the family squabbles.

Hector Elizondo is the magnate with months to live who hands over control to son Jimmy Smits. He reckons Cuban sugar is the new oil. "Today you're putting it in your coffee, tomorrow in your car," he says. One lump or two, I wonder.

OVERCROWDED: Ed Westwick and friends in Gossip Girl, the US teen soap based in New York STIFF UPPER LIP: Colin Mace and Alan Perrin in The 39 Steps The series is cast to the hilt with reliable performers, here given little to do that we haven't seen dozens of time before in TV series about rowing families. I fear this Cane may be for the chop before too long.

Back to real life with a bump in Sleeping With My Sister, a Cutting Edge documentary following two couples - half-brothers and sisters in Scotland and the US - over nine upsetting months.

Rather than be repulsed by the idea of siblings sleeping together, you may actually sympathise with their plight "in the grip of a powerful incestuous love". The only niggle is their willingness to allow cameras to film their every move and emotion in their battle to be together.

In Minneapolis, Tom and Stephanie are both married with three children. They grew up without knowing each other. Tom was adopted, not meeting his half-sister until he was seeking his biological mother when he was 35.

It was love at first sight for Nick and Danielle when they met for the first time three years ago. It was such an intensity of feeling, he says, that it felt natural in a way. "Confusing, yes. Wrong, no," he adds.

Their story made headlines after they were prosecuted for incest in the Scottish courts.

Nick was fostered at the age of one because of problems at home, about which we're not given details. The couple tell how they were caught having sex by their mother, who reported them to the police.

The nine months they're forced to live apart while police decide whether to prosecute are like a living hell for them. The mitigating circumstances they put to magistrates include GSA - genetic sexual attraction - which affects siblings who grow up apart and are reunited in adulthood.

Most people don't act on those feelings.

When they do, as Nick and Danielle did, the repercussions can be disastrous.